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Decided to walnut blast my intake valves myself as I was curious to see how much gunk built up within my intake tract around 10,000 miles. Been seeing a lot within the forum community with regards to these DIT engines getting pretty dirty. Since this is fairly new with the Subaru community and BMW shops/dealers are the only ones who seem to really do this type of service, I wanted to to get all the necessary equipment and do it myself as well as start doing it for other Subaru DIT engines around.

My car is a 2016 wrx and it has about 10,500 miles. I'm currently Cobb stage 1 with no engine related mods besides the Mishimoto dual oil catch can system. I will be getting TGV deletes after the winter is over along with a protune.

Step 1
Jack car up. Remove top engine cover as well as plastic undertray. The undertray as a total of 13 pop clips and 2 bolts.

Step 2
Release fuel pressure. First undo cap from gas tank. Then remove the fuel pump fuse which is located in the engine bay fuse box. The manual shows where this is. It's a #15 fuse. Start the car and run until it dies. Took about 2-3 minutes. Once it died, I tried starting again wit the gas pedal to the floor to make sure all fuel was gone. You can also use your Accessport if you have one to monitor fuel pressure. It will be down around 10 or so instead of in the thousands.

Step 3Jack car up and remove peacock from radiator. Open up radiator cap to speed up process. Stop once you fill about 3.6 quarts (what manual says to remove intake manifold).

Step 4Remove Intercooler 3 bolts with a bracket on right side along with the clamp for the hose on the right. loosen clamp on left side hose and 1 bolt at the top left.

Step 5Remove the 2 gas lines on the right side of the intake manifold. The top hose has a little blue clip that you pull out in order to release the hose. Remove bottom hose too. Put a few rags underneath to catch any fuel. Only a few drops came out with no pressure whatsoever.

Last edited by Subie53013; 12-01-2017 at 09:33 PM.
Reason: Removing part about offering the service...

Step 6All this step involves is removing all of the hoses and electrical plugs from the intake manifold. Once you start removing the intake manifold, you will be able to spot if you missed anything. One tip is to buy assorted color makers and mark each end so you know what goes where. Subaru already does this with a few of the hoses from the factory but not all of them. Also, remove the EGR valve coming from manifold. Be careful as there is a metal gasket at the end of the first part of the EGR system coming from the manifold. The little hose adapter that the gas lines came from also needs to come out. You need to remove the bottom hoses from the little piece and one of them has a little clip you have to pull out too.

Next, Remove the (Don't know the name of this) Must be part of the TGV assembly. 3 bolts. Be careful of the o-rings. They are black on the top of this unit and then orange on the bottom which connects to the head ports.

This is what the intake ports and valves look like after 10,500 miles!!!!

Step 9
You can finally now clean the intake valves!!!. Make sure to close the valves for each cylinder you work on. Use a socket wrench on the crank bolt.I use a vacuum adapter from Bavarian autosport, No one makes one for the WRX so I guessed at a size which was a little too small but I used a piece of rubber to block any open space in the port. The wand from the blaster can fit within this little hole through the vacuum adapter so as you blast, the shop vac will suck up all the pieces while you work to make it less messy. A little mess happens but not as much as if you didn't have this adapter. This stuff shoots fast and goes everywhere if its open!

Step 12
Put fuse back for fuel pump in engine bay fuse box. Add coolant back in to radiator. Start the car up, let warm up. Check all around to make sure there are no leaks and that everything is working properly. Use accessport to monitor data if you have one. Take it for a drive and take a log. If you don't have an accessport, just drive it around and once warm, get on it to make sure everything is good. If I was able to notice the improvements I listed in the beginning of this post from only being 10,500 miles, if you have 30K+ miles, you will notice a huge difference.

I wish i could do an EGR delete but being in Mass, emissions would be a pain to get through. Update: worked out with my tune and getting inspection I will see if my tuner can do something where I can avoid failing inspection. I truly believe that this new FA20 DIT platform is a great and big step forward for Subaru. Even when you come up with a brilliant idea for a new engine, there will be a few drawbacks that can affect the longevity...in our case it's the intake valves getting gummed up from not having any fuel mixture to clean the valves.

The best first step is to get some type of oil catch can system or AOS. EGR delete will also drastically slow down the build up from the manifold to the valves. A tune is also another must with these cars as the stock tune is crap..preaching to the quire, i know...

Forgot to mention. Put car in neutral and crank engine with ratchet from crank pulley and use flashlight to see in the port you're gonna start with and make sure the valves are closed. Repeat as you move to each new cylinder!

Props for doing it yourself..but every 10K is seems excessive. For my driving, thats every 8 months. No way am I doing it that often.

Hell, I'll wait till the car starts misfiring and then go have it done.

Thanks. I put on the dual catch can system so I won't have to do this every 10k miles. Will be doing tgv deletes and hopefully egr delete if the tuner can cause me to not fail Emissions inspection every 2 years. My recommendation is to put the oil catch can system on to greatly reduce carbon build up over time so you won't have to do cleaning nearly as often. Might do it again in 10k miles just to see how much less carbon built up with having the catch can system and deletes. No point in cleaning valves if you're not gonna do something to combat the one major drawback of having a DIT engine. All positives with this engine but that one big drawback... When you can eliminate that drawback, these engines will perform much better as well as last much longer with less risk.

Hopefully SOA realizes this is an issue and dealers start to offer the service. Props for doing on your own, your detail to the process is appreciated. I'm at 33k now, I can only imagine what mine looks like.

Hopefully SOA realizes this is an issue and dealers start to offer the service. Props for doing on your own, your detail to the process is appreciated. I'm at 33k now, I can only imagine what mine looks like.

I am pretty much right behind you. I just had a Terra Clean service done at 30k, i need to install my Crawford AOS, at least it will help a little bit and the Terra Clean at least beneficial but not to the point of this. Once i notice substantial change in performance i will be seeking out a shop to do it OR its a long road trip to see the OP, lol. I am surprised my mileage is still pretty close to what my 15 is rated for and i am stage 2.

Hopefully SOA realizes this is an issue and dealers start to offer the service. Props for doing on your own, your detail to the process is appreciated. I'm at 33k now, I can only imagine what mine looks like.

Seriously! Gonna try to find an email of someone important within SOA and share this thread...

Quote:

Originally Posted by Cisco Kidd

I am pretty much right behind you. I just had a Terra Clean service done at 30k, i need to install my Crawford AOS, at least it will help a little bit and the Terra Clean at least beneficial but not to the point of this. Once i notice substantial change in performance i will be seeking out a shop to do it OR its a long road trip to see the OP, lol. I am surprised my mileage is still pretty close to what my 15 is rated for and i am stage 2.

Great detailed write up and great job!

Thank you! Good luck with everything. If you have that many miles compared to what I have, you might be surprised with how much build up there is.

I would be tempted to have some custom TGV-delete style plates made with a hole in the side and capped off at the top to avoid having to remove the intake manifold. combine that with a walnut blaster hose designed to plug into it and all you'd have to do is make sure those valves are closed and you can blast away. maybe this is a bit simplistic but if it worked it would turn this from a nightmare into a slightly more complicated TGV delete install.

I would be tempted to have some custom TGV-delete style plates made with a hole in the side and capped off at the top to avoid having to remove the intake manifold. combine that with a walnut blaster hose designed to plug into it and all you'd have to do is make sure those valves are closed and you can blast away. maybe this is a bit simplistic but if it worked it would turn this from a nightmare into a slightly more complicated TGV delete install.

Hmmmm as long as you can find a way to get a shopvac attached to it then it will work...but how would you get one on a TGV from the side? I think I'm going to copy Unabomber's idea and use the OEM TGVs and create a vac/blaster setup on top of it.

I would be tempted to have some custom TGV-delete style plates made with a hole in the side and capped off at the top to avoid having to remove the intake manifold. combine that with a walnut blaster hose designed to plug into it and all you'd have to do is make sure those valves are closed and you can blast away. maybe this is a bit simplistic but if it worked it would turn this from a nightmare into a slightly more complicated TGV delete install.

Quote:

Originally Posted by TheSilentCircus

Hmmmm as long as you can find a way to get a shopvac attached to it then it will work...but how would you get one on a TGV from the side? I think I'm going to copy Unabomber's idea and use the OEM TGVs and create a vac/blaster setup on top of it.

In theory, this would be awesome. However, I think this would be tough. Having access to the full port with nothing in the way, to me anyways, seems pretty important to do a good job. If you had to go through the TGV's and the plates, etc, it would be tough for the blasting to get all the way down to the valves and the stems. I know these blasters are pretty powerful but still not sure if this would work out. Also, I blasted the whole intake manifold as that was pretty dirty which you can see in the pictures I posted.

@Subie53013, That is a great writeup! I have been looking into what it would take to do this myself, and your writeup is a big help!

Removing the Coolant and fuel lines are for sure the proper way to remove your intake manifold, but I did read a post on the Forester Forums about a guy who was able to remove the Intake Manifold without removing those hoses. He was able to fold it back towards the firewall to keep it out of the way.

@Subie53013, That is a great writeup! I have been looking into what it would take to do this myself, and your writeup is a big help!

Removing the Coolant and fuel lines are for sure the proper way to remove your intake manifold, but I did read a post on the Forester Forums about a guy who was able to remove the Intake Manifold without removing those hoses. He was able to fold it back towards the firewall to keep it out of the way.

1. Which Media Blaster kit did you get from Bavarian Motorsport, and which Vacuum Adapter did you use?

2. Can you give more details on how you modified the vacuum adapter to fit on the WRX?

3. How are you able to be 100% sure that the valves are closed before you blast them?

4. Do you have any issues with your Mishimoto Catch Can Hoses leaking, oozing/sweating oil, or being to smell oil/fuel from them?

5. What kind of engine oil have you been using?

It is re-assuring that your valves don't look that bad after 10k miles! I have been waiting a long time for someone to do a write-up on walnut blasting for the FA20DIT, thanks for making this for us!

Thanks for the info! The reason i removed the whole manifold was because I wanted to clean that as well. Was not going to blast that on top of car as the mess would have been crazy. You can see how dirty even the intake manifold ports and egr port got with the pictures. I heard the harbor freight blasters clog a lot too. For some reason, the link to the page where I can see the exact kit only brings you to main site. So go to Bavarian autosport website and paste B1100001 into the search button. That is the kit I got.

I bought this kit as I figured that would be smaller and it's about $80 for just that piece alone so I didn't want to get a bigger one and have to send it back after taking my car apart. Sucked cause no one at Bavarian knew the dimensions of the adapters and wouldn't even do me the favor of measuring the pieces so I could know which one comes closest to the WRX port dimension. BMW dealers didn't even know what the port dimensions were for their cars...

To answer the rest of your questions:

2. Can you give more details on how you modified the vacuum adapter to fit on the WRX?I just took a piece of rubber and cut it to fit the dimensions of the port which you can get online. Mishimoto has it on their website somewhere and it's 60mm X 28.7mm. Could not find all the BMW port sizes for their DI cars...came up with nothing except a pdf of an older m3 that was not DI and was not an option when picking out the vacuum adapter

3. How are you able to be 100% sure that the valves are closed before you blast them?When your rotating the crank (clockwise of course) with ratchet (I used a long 1/2 drive so I could work while looking into the port I was gonna blast with a flashlight. Look in and you will be able to see the valves open and close. Make sure the car is in neutral so it spins easily. Didn't take much force at all. You will see them pushed in when open and they will pull back while rotating crank and you will see when they stop once they are all the way back.)

4. Do you have any issues with your Mishimoto Catch Can Hoses leaking, oozing/sweating oil, or being to smell oil/fuel from them?No issues yet whatsoever. Getting the hoses onto the catch can for the PCV valve and back of intake manifold seemed impossible with the size of those hoses so I used a little lube and it went on much easier. Make sure to tighten clamps good. The most important hose to make sure is on good, well is all of them, but more importantly the PCV valve hose as that takes the most pressure and is the hose that will collect the majority of that oily water like solution.

5. What kind of engine oil have you been using?Pennzoil Platinum 5w30 which is $24 at walmart for a 5qt. I change it every 3,500 miles along with a new oem filter..